Abstract
We prove two ZFC inequalities between cardinal invariants. The first inequality involves cardinal invariants associated with an analytic P-ideal, in particular the ideal of subsets of ω of asymptotic density 0. We obtain an upper bound on the ∗-covering number, sometimes also called the weak covering number, of this ideal by proving that cov∗(Z0) k d. Next, we investigate the relationship between the bounding and splitting numbers at regular uncountable cardinals. We prove that, in sharp contrast to the case when k = ω, if k is any regular uncountable cardinal, then sk≤bk.
| Original language | English |
|---|---|
| Pages (from-to) | 187-200 |
| Number of pages | 14 |
| Journal | Fundamenta Mathematicae |
| Volume | 237 |
| Issue number | 2 |
| DOIs | |
| State | Published - 2017 |
Bibliographical note
Publisher Copyright:© Instytut Matematyczny PAN, 2017.
Keywords
- Asymptotic density
- Cardinal invariants
- Dominating number
- Weakly compact cardinal
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